Apes ch 9 species approach
Key Concepts
Human effects on extinction rates
Understanding biodiversity and extinction
How human activities endanger wildlife
Preventing extinction
Reconciliation ecology
Core Case Study: The Passenger Pigeon: Gone Forever
Passenger pigeon hunted to extinction by 1900
Commercial hunters used a "stool pigeon”
Archeological record shows five mass extinctions
Human activities: hastening more extinctions?
Species Extinction
Local extinction: A species is extinct in one area but still lives elsewhere
Ecological extinction: A few members are left but no longer play a role in the biological community
Biological extinction: The species is no longer found anywhere on the planet
Human Activities Are Destroying and Degrading Biodiversity
Human activity has disturbed at least half of the earth’s land surface
Fills in wetlands
Converts grasslands and forests to crop fields and urban areas
Degraded aquatic biodiversity
Some Human Activities Cause Premature Extinctions; the Pace Is Speeding Up
Conservative estimates of extinction = 0.01-1.0%
Growth of human population will increase this loss
Rates are higher where there are more endangered species

Tropical forests and coral reefs, wetlands and estuaries—sites of new species—being destroyed
Extinction Rates
Background (natural) rate of extinction: 99.9% of all species that have existed have goon extinct
Mass extinction: 25% - 70% or more
Extinction spasm: Large number of species go extinct in a very short time (less than 1000 years)
Problems Estimating Extinction Rates
Extinction not easily documented over time
Many species remain unidentified
Little is known about most identified species
Estimating Extinction Rates
Species-area relationships: 90% loss of habitat results in 50% species loss
Population viability analysis (PVA): Species specific calculation on how many years before the
population will become extinct
Minimum viable population (MVP): Minimum number a population can have and survive in the wild
Minimum dynamic area (MDA): minimum amount of area a species needs to survive
Endangered and Threatened
Endangered species: So few individuals that the species could soon become extinct over all or part of
its natural range
Threatened (vulnerable) species: Still abundant but numbers are dropping and likely to become
endangered
Causes of Depletion of Wild Species
Human population growth
Increasing per capita resource use
Endangered centers of biodiversity
Environmental destruction
Spread of opportunistic species
Importance of Wild Species

Rebuilding biodiversity is slow
Instrumental value
Genetic information
Eco-tourism
Ecological value
Intrinsic value
Species Are a Vital Part of the Earth’s Natural Capital
Instrumental value
Use value
Ecotourism: wildlife tourism
Genetic information
Nonuse value
Existence value
Aesthetic value
Bequest value
Ecological value
Science Focus: Using DNA to Reduce Illegal Killing of Elephants for Their Ivory
1989 international treaty against poaching elephants
Poaching on the rise
Track area of poaching through DNA analysis of elephants
Elephants damaging areas of South Africa: Should they be culled?
Are We Ethically Obligated to Prevent Premature Extinction?
Intrinsic value: existence value
Edward O. Wilson: biophilia phenomenon
Biophobia

Science Focus: Why Should We Care about Bats?
Vulnerable to extinction
Slow to reproduce
Human destruction of habitats
Important ecological roles
Feed on crop-damaging nocturnal insects
Pollen-eaters
Fruit-eaters
Unwarranted fears of bats
Causes of Premature Extinction of Wild Species
Habitat Loss and Degradation
Greatest threat to species
“HIPPO”
Habitat destruction
Invasive species
Population (humans) growth
Pollution
Overharvesting
Case Study: A Disturbing Message from the Birds
Habitat loss and fragmentation of the birds’ breeding habitats
Forests cleared for farms, lumber plantations, roads, and development
Intentional or accidental introduction of nonnative species
Eat the birds
Case Study: A Disturbing Message from the Birds

Seabirds caught and drown in fishing equipment
Migrating birds fly into power lines, communication towers, and skyscrapers
Other threats
Oil spills
Pesticides
Herbicides
Ingestion of toxic lead shotgun pellets
Case Study: A Disturbing Message from the Birds
Greatest new threat: Climate change
Environmental indicators
Economic and ecological services
Some Deliberately Introduced Species Can Disrupt Ecosystems
Most species introductions are beneficial
Food
Shelter
Medicine
Aesthetic enjoyment
Nonnative species may have no natural
Predators
Competitors
Parasites
Pathogens
Threats from Nonnative Species
Case Study: The Kudzu Vine
Imported from Japan in the 1930s

“ The vine that ate the South”
Could there be benefits of kudzu?
Prevention Is the Best Way to Reduce Threats from Invasive Species
Prevent them from becoming established
Learn the characteristics of the species
Set up research programs
Try to find natural ways to control them
Other Extinction Threats
Hunting and Poaching
Predators and Pest Control
Exotic Pets and Decorative Plants
Climate Change and Pollution
Other Causes of Species Extinction
Pesticides
DDT: Banned in the U.S. in 1972
Bioaccumulation
Biomagnification
Case Study: Where Have All the Honeybees Gone?
Honeybees responsible for 80% of insect-pollinated plants
Dying due to?
Pesticides
Parasites
Bee colony collapse syndrome
Case Study: Polar Bears and
Global Warming
Environmental impact on polar bears

Less summer sea ice
PCBs and DDT
2007: Threatened species list
Illegal Killing, Capturing, and Selling of Wild Species Threatens Biodiversity
Poaching and smuggling of animals and plants
Animal parts
Pets
Plants for landscaping and enjoyment
Prevention: research and education
Rising Demand for Bush Meat Threatens Some African Species
Indigenous people sustained by bush meat
More hunters leading to local extinction of some wild animals
Hunting of bush meat is connected to the spread of AIDS
Protecting Wild Species: The Research and Legal Approaches
International Treaties: CITES and CBD
Convention on International Trade in Endangered Species (CITES) 1975
Convention on Biological Diversity (CBD)
U.S. National Laws: Lacey Act (1900) Prohibits transport of live or dead animals across state line
without a federal permit
Endangered Species Act (1973, 82, 85, 88) Identifies and lists endangered and threatened species
Endangered Species Act
Private versus public poverty rights
Win-win compromises
Habitat conservation plans (HCPs)
Voluntary candidate conservation agreements
Weaken or strengthen the act?

Science Focus: Accomplishments of the Endangered Species Act
Species listed only when serious danger of extinction
Takes decades for most species to become endangered or extinct
More than half of the species listed are stable or improving
Budget has been small
Protecting Wild Species: The Sanctuary Approach
Wildlife refuges and protected areas
Gene banks, botanical gardens, and farms
Zoos and Aquariums
U.S. has 542 federal refuges for wildlife; most are suffering from environmental degradation
Gene Banks, Botanical Gardens, and Wildlife Farms Can Help Protect Species
Gene or seed banks
Preserve genetic material of endangered plants
Botanical gardens and arboreta
Living plants
Farms to raise organisms for commercial sale
Zoos and Aquariums Can Protect
Some Species
Techniques for preserving endangered terrestrial species
Egg pulling
Captive breeding
Artificial insemination
Embryo transfer
Use of incubators
Cross-fostering

Reconciliation Ecology
Establishing and maintaining new habitats
Being good neighbors to wildlife
Reward voluntary conservation efforts
The Precautionary Principle
Species: primary components of biodiversity
Preservation of species
Preservation of ecosystems